Transformer.



PATENTED DEC. 10, 1907.

J. J. FRANK. TRANSFORMER.

APPLICATION FILED MAY 1. 1907.

Oppositelg Wound Inventor:

John J. Frank, I b 3M JItt'g,

Wntnesses /Z 4w. 3-

UNITED STATES PATENT oEEIoE.

JOHN J. FRANK, OF SCHENECTADY, NEW YORK, ASS IGNOR TO GENERAL ELECTRIC COMPANY,

A CORPORATION OF NEW YORK.

TRANSFORMER.

Specification of Letters Patent.

Patented Dec. 10, 1907.

Application filed May 1. 1907- Serial No. 371,284.

ectad county of Schenectady, State of New ork, have invented certain new and useful Improvements in Transformers, of

" which the following is a specification.

ing a plurality of sets of seconda .lOv

connections My invention relates to transformers hav coils on din'erent portions of the core,"an particularly to transformers designed for operation on three-wire distribution circuits.

- In order to prevent the transformer regulation from being impaired by an unbalancing of the load on a three-wire distribution system, it is customa. in transformers intended for use on suc circuits to connect each secondary coil of one set directly in series with the secondary coil of the other set on the other portion of the core, so that a coil of each set is included between each outer wire and the neutral. In the usual construction of core-type transformers having a pair of secondary coils on each leg of the core, the connection is usually made as follows: one outer main is connected to the upper end of a secondary coil; from the lower end of this coil 5, connection extends across the bottom of the transformer to the lower end of a coil on the other leg; from the upper end of this second coil a connection extends across the top of the transformer to the up er end of the other coil on the first leg; an a third connection extends from the lower end of the last-mentioned coil across the bottom of the transformer to the lower end of the other coil on the second leg. It will be seen that these connections ,form a coil of one-and-one-half turns, carrying thefull secondary current and the length of each turn of this coil in the usual construction "of core-type transformers is approximately.

equal to the length of the core. The 001] formed by these connections produces a crossmagnetization of the core and introduces a reactance into the second circuit, which impairs the regulation; of ,tfe transformer. j

Furthermore, since this coil is parallel with; the plane of the laminations,1ts flux is at right-angles to the laminations," and conse-.

quently produces eddy currents in the core; which increase the heating efficiency of the transformer. the. My inven inso v secondary coils tint and lower the J. FRANK, a citi-' the circuit formed by them is substantially V non-inductive. I accomplish this result by ''winding the two secondary coils on each leg oppositely with respect to each other, 0011-,

nectingv one end of one coil with the corresponding end of a coil on the other leg of the core, connecting the other end of this second coil with a corresponding end of the other coil on the'same leg of the core, and connecting the'other end of the last-mentioned coil with the correspondin end of the other coil on the first-mention leg. with this arrangement only two cross-connections are employed between the secondary coils on op. posite legs, and these two connections lie parallel with and adjacent toeach other, so as to form a substantially non-induc tive circuit.

My invention Wlll best be understood by reference to' the accompanying drawing's,'in

- which Figure 1 shows, partly in cross-section, a

transformer of the type to which my invention relates; and Fig. 2 shows diagrammatic ally the coils connected in accordance with. my invention. v

In the dra s, A represents the magnetic core, on eac leg of which are mounted one or more primary coils B and B, and two or more secondary coils C '0 This coil arrangement, shown in Fig. 1, is a standard arrangement, except that the two secondary coils on the core are in the present case oppositel wound, and if twoprimary coils are emp eyed, as shown, these also are. preferably 01)}Fflt0lY-WOHllde connections of the several coils to each other'are shown di ammaticall in Fig. 2,in which theleft-ha y coil of each group may be considered the 'outer coil on that leg of the core. I) I) represent the primary terxmms. The relative connections of the primary coils are comparatively unimportant, .as the rimary current is com aratively small. t'wo oppositely-woun primary coils are placed on each'leg, as indicated, the

connection between the coils may-be made as-shown. c c represent theout'erm'ains-of. theseeondary circuit, and dthe connection.

vto the neutral of. "'a' three-wire distribution m. As'will becleatlseen-ns v w s i which is the inner coil on the other'leg, then I from the top of this coil to the coil C fwhich is the outer coil onthe same leg with the stantially non-inductive.

What I- claim as new and desire to secure by Letters Patent of the United States, is, 1. In a transformer, a magnetic core, a plurality of sets of secondary coils on diferent portions of said core, and direct series connections-between each secondary coil of one set and a secondary coil on another set,

' said connections being arranged to form .a

substantially non-inductive circuit.

'2. In a transformer, a magnetic core, a

plurality of sets of secondary coils on different portions of said core, and conductors connecting in series secondary coils on dif-. ferent portions of the core, each of said conductors lyin parallel with and adjacent to. a

second con uctor carrying current in the opposite direction. v

3. In a transformer, a magnetic core, a pair of oppositely-wound secondary coils on each leg of the core, a connection from one end of one of said coils to the corresponding end of a second coil-onthe other leg of the' core, a connection from the other end of the second coil to the corresponding end of the other coil'on the same leg, and a connection from the other end of the last-mentioned coil to the corresponding end of the other coil on the same leg with the first-mentioned coil}.

In withess'whereof, I have hereunto set my hand this th day of April, 1907.

JOHN J. FRANK.

' Witnesses:

BENJAMIN B. HULL. HELEN Onnonn. 

